Railway signaling.



J. S. HOLLIDAY.

RAILWAY SIGNALING.

APPLIGATION FILED JULY 26. 1913.

Patented Feb. 9, 1915.

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RAILWAY SIGNALING.

APPLICATION FILED JULY 26.1918.

1,127,438. Patented Feb. 9, 1915.

4 SHEETS-SHEET 2 WITNESSES ENVENTOR wfiawm WWW J. S. HOLLIDAY.

RAILWAY SIGNALING.

APPLICATION FILED JULY 26, 1913.

Patented Feb. 9, 1915.

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RAILWAY SIGNALING.

APPLICATION FIL-ED JULY 26,1913.

Patented Feb. 9, 1915.

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INENTOR WITNESSES To all witom it may concern JOHN i3. HOLLIIDAY, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO THE .UNION' SWITCH &.SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

Specification of Letters Patent.

RAILWAY SIGNALING.

Application filed July 26, 1913. Serial No. 781,286.

' Be it known that 1, JOHN S. /HOLLIDAY,

' aoitizen of the United States, residing at is a specification.

Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Railway Signaling, of which the following My invention relates to track circuit apparatus for railway signaling, and particularly to apparatus for alternating current track circuits.

I will describe two forms of apparatus embodying my invention, and will then point out the novel features thereof in claims. 5

In the accompanying-drawings, Figure 1 is a diagrammatic View showing a section of track of a direct current electric railway provided with one form of track circuit'apparatus embodying my invention, both track rails of the railway being included in the circuit of 'thepropulsion current. Fig. 2 is a diagrammatic view showing a section of track of an alternating current electric railway provided with another form of track circuit apparatus embodying my invention Fig. 3 is a view showing in front elevation. a device B shown in Fig. 1. Fig. 3 1s a" sectional view on the line III-III of Fig. '3 looking in the directionindicated by the arrows. Fig. 4 is a view showing in front elevation a device B shown in Fig. 2. Fig.

" 1 is a sectional view on the line IVIV of F ig. 4 looking in the direction indicated by thearrows. Fig. '5 is a diagrammatic view showing a section of track of an electric railway provided with track circuit apparaonly one track railbeing included in the circuit of the propulsion current. Fig. 6 is a diagrammatic view showing a section of track of a steam railway provided with track circuit apparatus embodying my invention. Similar reference characte s refer to similar parts in each of the views.

Referring first to Fig. 1, the numerals 1,

2 designate the track rails of a railway, a section A of which is electrically separated from the rails of the adjoining sections by insulated joints 3. The railway here shown is an electric railway the propulsion current for which is supplied from a direct current generator C, one terminal of which is nected with the track rails 1 sulated joints 3 to conduct the propulsion current around these joints in a usual and well known manner.

The track section A is provided with a track circuit comprising the track rails 1 and 2 of the section, a source of alternating signaling current, and a track relay. As here-shown, the source of signaling current is a transformer T whose secondary is connected with the track rails and whose primary is connected with transmission mains 7 to which alternating signaling current is supplied by a generator G. The track relay, which is designated R, is as here shown tor 18 and two stator windings 19 and 20. Winding 20 is connected with the track rails, and winding 19 is connected with a secondary 8 of a transformer T whose primary is connected with the transmission mains 7. The rotor 18 operates a contact 21 which is included in a local circuit 10 which controls a signal S governing traflic through block section A. The local circuit 10 for signal S is supplied with energy by another secondary 9 of transformer T With only the apparatus thus far mentioned, it will be seen that when a car or train occupies the track rails at or near the point at which the secondary of transformer T is connected with the rails, the wheels and axles of the car or train would short-circuit this secondary so that aheavy current would be drawn therefrom. In order to limit the current which is drawn at such times from the transformer T, and yet not impose an undesirable impedance in the track circuit, I interpose in the connection between the transformer secondary and one track rail a device B which I will now describe.

Referring to Figs. 3 and 3 the device B as here shown comprises a magnetizable field 11, formed of a plurality of laminations of transformer iron clamped together by rivets 15. This field is provided with a a polyphase type of relay comprising a'rowinding 12, which, as shown in Fig. 1, is

included in the connection between the sec- J mum current drawn'from the transformer T ondary of transformer T and track rail 2.

The fieldll is substantially U-shaped; lo-

cated. between the poles formed by the legs of the field is a rotor member 13 formed of a plurality of laminations of transformer iron clampedtogether between two end plates 30 and 30* of electro conductive material such as copper. This member 13 is mounted on an arbor 14: which. is supported in suitable bearings which are not shown. Member'l3 is provided with a closed circuit of electro-conductive material comprising the two copper end plates and two bars 16 passing through the member and electrically connected with both end plates. These bars 16 serve also to clamp the end plates and laminations together. member 13 is limited to oscillation through a. small arc of a circle by two stationary stops 22, 22 between which moves a tongue 17 projecting from a collar 21 fixed on the arbor 14. Member 13 is biased to the position shown, that is, to. such position that tongue 17 engages stop 22*, by a counterweight'23 comprising a screw 23 fitting .into a threaded boss on collar 24 and a nut 23'. adjustable on the screw.

Referring to Figs. 1 and 3, the "operation of the device B is as follows: When the member 13 is in the position shown, a certain amount of alternating magnetic flux produced by current in the winding 12 passes through the closed circuit formed by the bars 16 and the end plates. This alter nating flux causes current to flow in this circuit, and the eflectcf this current is to produce torque tending to turn member'13 in clockwise direction as viewed in Fig. 3, against the action of counterweight 23. The device is so proportioned that at the maxiwhen section A is unoccupied, the torque on member 13 is not sufficient to'move this member against the action of counterweight 23. When, however, a car or train occupies the rails of section A it reduces the impedance in thecircuit'of thesecondary of transformer T and the current in this circuit therefore increases. This increased current in winding 12 produces suificient flux to "move member 13 against the action of the counterweight,so that tongue 17 moves toward stop 22.- When member 13 is in this position, the plane of the closed circuit carried thereby is more nearly parallel with the i direction of the flux passing between the poles of field 11 than before, sothat a smaller proportion of the total flux passes through this closed circuit and a larger pro-' portion will pass through th member 13 outside of the closed circuit. The impedance of the entire devicemeasured across the terminals of winding 12 is then increased, for the reason that a greater amount of flux flows in the magnetic circuit in proportion The movement of current drawn from the transformer T with ,to the current in winding 12. Although the member 13 in this position is greater than I when the track rails are unoccupied, still the power taken from the transformer is actually less than when the rails are unoccupied; the reason being that when the imthe rails are unoccupied.

It will be seen that direct current in winding 12 has no tendency to produce torque on member 13, because a constant magnetic flux in member 13 will not produce current in the closed circuit which includes bars 16; hence, the presence of direct propulsion current in winding 12 hasno efl'ect on the device B other than to magnetize the field core 11.

Referring-now to Fig. 2, the apparatus Fig. 1, except that in Fig. 2 the propulsion generator C is'an alternating current generator. T he propulsion current and the signaling current differ in frequency, the frequency of the former usually being 25 cycles and that of the latter 60 cycles. B is a device which, like the device B in Fig. 1, is placed between the transformer T and the track to limit the power drawn from the transformer when the track is occupied. This device B is operated by current of the signaling frequency, but not by current of the propulsion frequency.

Referring to Figs. 4 and 4 the device B comprises a magnetizable field 11 formed of a plurality of laminations of transformer iron, clamped together by rivets 15. This field, as here shown, is E-shaped, having three projecting legs 25, 25, and 25". The middle leg 25 is provided witha winding .12 which, as shown in Fig. 2, is included in the connection between the transformer secondary'and one track rail 2. Mounted between the two outside legs 25 and 25 is a member '13 which is similar to the member '13shown in Fig. 3 a d hereinbefore described. The end of le 25 is also in close proximity to member 13 as shown. It will be seen that there are two paths for the ma gnetic flux produced by current in winding 12, viz., through leg 25", and through leg- 25". Both of these paths includea part of the member 13. The bars 16 are so located that when member 13 is in the .position shown,'the same proportion of the flux in each of the two paths will flow through the closed circuitwhich includes bars 16 and the end plates. Hence, if the fliixes in these two paths are equal, the amounts of flux in the shown therein is similar to that shown in this flux which passes through leg 25 will set up a torque tending to turn. the rotor counter clockwise, so that a plane through bars 16 will be cut by a minimum of flux.

Similarly a clockwise torque will be set up by the flux entering leg 25". If the fluxes in the two paths are equal, the resultant torque is zero. Means are provided for causing the flux produced by 25 cycle current in winding 12 to be equal in the two paths, but for causing the flux produced by 60 cycle current to predominate in the path including leg 25*. As here shown, this means consists in making the air gap 27 between leg 25 and member 13 greater than air gap 27 between leg 25 and member 13, and in providing a band 26 of electro-conductive material encircling leg 25. The band 26 forms a short-circuited secondary and acts in the well known manner to decrease the magneto-motive force tending to produce flux along the path including leg 25*. The band 26 and the difference between the .lengths of air gaps 27 and 27, are so proportioned that with 25 cycle current in winding 12 the fluxes in the two 'magnetic pathsare balanced, but that with 60 cycle current in winding 12 the flux in the path including leg 25 is greater than that in the path including leg 25*. Hence, any propulsion current which may flow in winding 12 has no tendency to produce torque on member 13 Referring to Figs. 2 and 4, the operation of the device B is as follows: When the member 13 is in the position shown in Fig. 4, a certain amount of flux produced by the signaling current in the winding 12 passes through the closed circuit formed by the bars 16 and the end plates. This flux causes current to flow in this circuit and the effect of this current is to produce torque tending to turn member 13 in clockwise direction as viewed in Fig. 4 against the action of counterweight 23. The device is so proportioned that at the maximum current drawn from transformer T, when section A is unoccupied, the torque on member 13 is not sufiicient to move this member against the action of counterweight 23. When, however, a car or train occupies the rails of sectiorl- A, it reduces the impedance in the circuit of the secondary of transformer T, and the current in this circuit therefore increases. This increased signalingcurrent in winding 12 produces sufficient flux to move member 13 against the action of the counterweight so that tongue 17 then moves toward stop 22. Whenthe member 13 is in this position, the plane of the closed circuit carried thereby is more nearly parallel with the direction of the flux passing through the magnetic circuit including leg 25*, so that a smaller proportion of the total flux in this path passes through this closed circuit and a larger proportion passes through the member 13= outside of the closed circuit. The impedance of the entire device measured across the terminals of winding 12 is then increased. Although the current drawn from the transformer T with member 13* in this position is greater than when the track rails are unoccupied, still, the power' taken from the transformer T is actually less than when the rails are unoccupied; the reason being the same as hereinbefore explained in describing device B shown in Figs. 1 and 3.

Referring now .to Fig. 5, l have here shown a section of track of a direct current electric railway, one rail only oi the two track rails beingincluded in the circuit'of the propulsion current. Rail 2 is electrically continuous, and rail 1 is divided by insulations 3 to form block sections. One terminal of the generator C is in this case connected directly with the continuous rail 2. In a railway of this type there is generally a difference of potential of the direct propulsion current betweenv the two track rails 1 and 2, .but as pointed out hereinbe-fore the device B is not responsive to this current. The operation of the apparatus shown in Fig. 5 will be apparent from the foregoing.

explanation of the operation of the apparatus shown in Fig. 1.

In Fig. 6 I have shown a section of track of a steam road, both track rails being divided by insulations 3. The apparatus shown in this View is similar to that shown in Fig. 1, and the operation will be apparent from the foregoing explanation of Fig. 1.

Although I have herein shown and described only two forms of track circuit apparatus embodying my invention, it is understood that various changes and modifications may be made*therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described what I claim is:

1. An impedance device comprising a winding, and a movable member comprising a closed circuit of electro-conductive material located in the path of the magnetic flux produced by current in said winding, the movement of the member being between two positions in which different proportions of the flux pass through the closed circuit.

2. An impedance device comprising a magnetizable field having three projecting legs, a winding on the middle leg, a movable member comprising a'closed circuit of electro-conductive material located inboth paths of magnetic flux from the middle leg to each of the other legs,

my invention,

tance, and a closed circuit of electro-conductive material surrounding the'outside leg which is separated from said movable member-by the alrgap of least reluctance.

- 3.. An impedance device comprlsing a;

winding, a'magnetizable coregfor said windmg havmg two paths in multiple for the flux'produced by current in sald winding,

a inova'ble member having .a closed circuit,

of electroconductive. material interposed in 1.0 both of 'said'paths, the air gaps between said member. and-the core being. unequal in the two paths,fand a closed circuit of electroconductive material surrounding the path havingthe' lesser air gap. 1o? .4; An impedance device. comprising a Winding, magnetizable field core having pathsin nul'tiple for the flux produced by current in said'winding, a movable themberlhaving'a-closed circuit of electro-con- 2o=ductive material located both of said paths, and means for balancing the fluxesin said'closed circuit from said two paths when.

alternatingpcurrenteof one frequency flows inYsaid." winding and for unbalancing the '25-: 'fli1x esin said closed circuit from said two paBths-fiwhenalternating current of another quency flows. in said winding.

5. impedance .devicecomprising a magnetizable field,-a winding for said field,

eo and a-gmagnetizableumember carrying a closed circuit of electro-conductive material mounted in the path of the magnetic flux flowing infsaid field, said member being movable between two, positions in which different proportions of the flux pass through the closed circuit.

6. impedance device adapted to be used in an electric circuitin which; alternating current of one value flows at onetime and alternating current of another-value flows at another time, said device comprising awinding, adapted to be energized from the circuit carrying alternating current," and a.

' member comprising a closed circuit'ofelec- 4 5 tro co'nductive material located in the path ofthe flux produced by current in said winding, said member being movable between two positions in which different proportions of the flux pass through said closed circuit,

and said .inember being biased to the position in which the greater proportion of flux passes through saidclo'sed circuit, said device"bein'g 'so adjusted that whenthealterfiatingzcurrnt ofle'sser. valuel-fldws in said windingthe torque exerted on' said member is'not suflicient to move the member in '0 position to its bias, but that .when the'fa te'r-f nating current of greater value flows in -said winding the torqueexerted on said. member is .suflicient to move the member to" the position in which thelesser proportion of flux passes through said closed circuit whereby the impedance offered by said device to the alternating current. flowing in its. winding is then increased. a

used in connection with an electric circuit carrying alternating currents'of two frequencies a and 6, current of frequency 6 having one value at one time and another value at another time, said? device comprising a winding adapted to be energized from the circuit carrying alternating currents, .a magnetizable field having two paths in multiple for the flux producedby currents in said winding, a member having a closed circuit of electro-conductive material located in both of said oaths, means for balancing the fluxes produced in said two paths by'alternating current of frequency a and for unbalancing the fluxes produced in said two paths by alternating current of frequency-b, said member being movable between. two positions .in which'dideren't proportions of the flux produced by the alternating current of frequency 1) pass through said closed c1r cuit, andsaid member being biased to the position in which the'greater proportion of said flux of frequency-b in, one path passes 7.:An impedance device .adapted to be 

